In existing Internet Protocol (IP) backbone networks, service providers normally engineer their IP backbone networks with sufficient bandwidth to handle network failures. Links within the IP backbone network are provisioned with spare capacity, such that in the event of a network failure, affected traffic may be rerouted from their normal routes to links having spare capacity. In practice, service providers will allocate some spare capacity in their backbone to ensure reliable transport services when the network experiences a failure. However, under normal conditions, the capacity built in to accommodate traffic resulting from a failure is not used. Because severe failures occur infrequently in well engineered networks, the spare capacity engineered for failure recovery is idle most of the time.
In existing IP networks, different classes of services may be offered by service providers, where each class of service is assigned a Quality of Service (QoS) marking. Traffic is differentiated based on its associated QoS marking as the traffic traverses the IP network. Currently, the lowest existing QoS marking is a “best effort” service, which does not guarantee performance (e.g. delay or loss) for the demand. However, when the IP network is being designed based on traffic forecasts, the IP network takes into account all existing traffic or service types, including the “best effort” service. Therefore, the spare capacity that is engineered for failure situations is idle most of the time, and could be utilized rather than being an unused resource.